Posts tagged neuroscience
Articles and news from the latest research reports.
A Gene Linked to Disease Found to Play a Critical Role in Normal Memory Development
It has been more than 20 years since scientists discovered that mutations in the gene huntingtin cause the devastating progressive neurological condition Huntington’s disease, which involves involuntary movements, emotional disturbance and cognitive impairment. Surprisingly little, however, has been known about the gene’s role in normal brain activity.
Now, a study from The Scripps Research Institute’s (TSRI’s) Florida campus and Columbia University shows it plays a critical role in long-term memory.
“We found that huntingtin expression levels are necessary for what is known as long-term synaptic plasticity—the ability of the synapses to grow and change—which is critical to the formation of long-term memory,” said TSRI Assistant Professor Sathyanarayanan V. Puthanveettil, who led the study with Nobel laureate Eric Kandel of Columbia University.
In the study, published recently by the journal PLOS ONE, the team identified an equivalent of the human huntingtin protein in the marine snail Aplysia, a widely used animal model in genetic studies, and found that, just like its human counterpart, the protein in Aplysia is widely expressed in neurons throughout the central nervous system.
Using cellular models, the scientists studied what is known as the sensory-to-motor neuron synapse of Aplysia—in this case, gill withdrawal, a defensive move that occurs when the animal is disturbed.
The study found that the expression of messenger RNAs of huntingtin—messenger RNAs are used to produce proteins from instructions coded in genes—is increased by serotonin, a neurotransmitter released during learning in Aplysia. After knocking down production of the huntingtin protein, neurons failed to function normally.
“During the learning, production of the huntingtin mRNAs is increased both in pre- and post-synaptic neurons—that is a new finding,” Puthanveettil said. “And if you block production of the protein either in pre- or post-synaptic neuron, you block formation of memory.”
The findings could have implications for the development of future treatments of Huntington’s disease. While the full biological functions of the huntingtin protein are not yet fully understood, the results caution against a therapeutic approach that attempts to eliminate the protein entirely.
Bioengineers Create Functional 3D Brain-like Tissue
Bioengineers have created three-dimensional brain-like tissue that functions like and has structural features similar to tissue in the rat brain and that can be kept alive in the lab for more than two months.
As a first demonstration of its potential, researchers used the brain-like tissue to study chemical and electrical changes that occur immediately following traumatic brain injury and, in a separate experiment, changes that occur in response to a drug. The tissue could provide a superior model for studying normal brain function as well as injury and disease, and could assist in the development of new treatments for brain dysfunction.
The brain-like tissue was developed at the Tissue Engineering Resource Center at Tufts University, Boston, which is funded by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) to establish innovative biomaterials and tissue engineering models. David Kaplan, Ph.D., Stern Family Professor of Engineering at Tufts University is director of the center and led the research efforts to develop the tissue.
Currently, scientists grow neurons in petri dishes to study their behavior in a controllable environment. Yet neurons grown in two dimensions are unable to replicate the complex structural organization of brain tissue, which consists of segregated regions of grey and white matter. In the brain, grey matter is comprised primarily of neuron cell bodies, while white matter is made up of bundles of axons, which are the projections neurons send out to connect with one another. Because brain injuries and diseases often affect these areas differently, models are needed that exhibit grey and white matter compartmentalization.
Recently, tissue engineers have attempted to grow neurons in 3D gel environments, where they can freely establish connections in all directions. Yet these gel-based tissue models don’t live long and fail to yield robust, tissue-level function. This is because the extracellular environment is a complex matrix in which local signals establish different neighborhoods that encourage distinct cell growth and/or development and function. Simply providing the space for neurons to grow in three dimensions is not sufficient.
Now, in the Aug. 11th early online edition of the journal Proceedings of the National Academy of Sciences, a group of bioengineers report that they have successfully created functional 3D brain-like tissue that exhibits grey-white matter compartmentalization and can survive in the lab for more than two months.
“This work is an exceptional feat,” said Rosemarie Hunziker, Ph.D., program director of Tissue Engineering at NIBIB. “It combines a deep understand of brain physiology with a large and growing suite of bioengineering tools to create an environment that is both necessary and sufficient to mimic brain function.”
The key to generating the brain-like tissue was the creation of a novel composite structure that consisted of two biomaterials with different physical properties: a spongy scaffold made out of silk protein and a softer, collagen-based gel. The scaffold served as a structure onto which neurons could anchor themselves, and the gel encouraged axons to grow through it.
To achieve grey-white matter compartmentalization, the researchers cut the spongy scaffold into a donut shape and populated it with rat neurons. They then filled the middle of the donut with the collagen-based gel, which subsequently permeated the scaffold. In just a few days, the neurons formed functional networks around the pores of the scaffold, and sent longer axon projections through the center gel to connect with neurons on the opposite side of the donut. The result was a distinct white matter region (containing mostly cellular projections, the axons) formed in the center of the donut that was separate from the surrounding grey matter (where the cell bodies were concentrated).
Over a period of several weeks, the researchers conducted experiments to determine the health and function of the neurons growing in their 3D brain-like tissue and to compare them with neurons grown in a collagen gel-only environment or in a 2D dish. The researchers found that the neurons in the 3D brain-like tissues had higher expression of genes involved in neuron growth and function. In addition, the neurons grown in the 3D brain-like tissue maintained stable metabolic activity for up to five weeks, while the health of neurons grown in the gel-only environment began to deteriorate within 24 hours. In regard to function, neurons in the 3D brain-like tissue exhibited electrical activity and responsiveness that mimic signals seen in the intact brain, including a typical electrophysiological response pattern to a neurotoxin.
Because the 3D brain-like tissue displays physical properties similar to rodent brain tissue, the researchers sought to determine whether they could use it to study traumatic brain injury. To simulate a traumatic brain injury, a weight was dropped onto the brain-like tissue from varying heights. The researchers then recorded changes in the neurons’ electrical and chemical activity, which proved similar to what is ordinarily observed in animal studies of traumatic brain injury.
Kaplan says the ability to study traumatic injury in a tissue model offers advantages over animal studies, in which measurements are delayed while the brain is being dissected and prepared for experiments. “With the system we have, you can essentially track the tissue response to traumatic brain injury in real time,” said Kaplan. “Most importantly, you can also start to track repair and what happens over longer periods of time.”
Kaplan emphasized the importance of the brain-like tissue’s longevity for studying other brain disorders. “The fact that we can maintain this tissue for months in the lab means we can start to look at neurological diseases in ways that you can’t otherwise because you need long timeframes to study some of the key brain diseases,” he said.
Hunziker added, “Good models enable solid hypotheses that can be thoroughly tested. The hope is that use of this model could lead to an acceleration of therapies for brain dysfunction as well as offer a better way to study normal brain physiology.”
Kaplan and his team are looking into how they can make their tissue model more brain-like. In this recent report, the researchers demonstrated that they can modify their donut scaffold so that it consists of six concentric rings, each able to be populated with different types of neurons. Such an arrangement would mimic the six layers of the human brain cortex, in which different types of neurons exist.
As part of the funding agreement for the Tissue Engineering Resource Center, NIBIB requires that new technologies generated at the center be shared with the greater biomedical research community.
“We look forward to building collaborations with other labs that want to build on this tissue model,” said Kaplan.
Testosterone in Healthy Men Increases Their Brains’ Response to Threat
Testosterone, a steroid hormone, is well known to contribute to aggressive behavior in males, but the neural circuits through which testosterone exerts these effects have not been clear.
Prior studies found that the administration of a single dose of testosterone influenced brain circuit function. Surprisingly, however, these studies were conducted exclusively in women.
Researchers, led by Dr. Justin Carré, sought to rectify this gap by conducting a study of the effects of testosterone on the brain’s response to threat cues in healthy men.
They focused their attention on brain structures that mediate threat processing and aggressive behavior, including the amygdala, hypothalamus, and periaqueductal gray.
The researchers recruited 16 healthy young male volunteers, who completed two test days on which they received either testosterone or placebo. On both testing days, the men first received a drug that suppressed their testosterone. This step ensured that testosterone levels were similar among all study participants. The amount of testosterone administered in this study only returned testosterone levels to the normal range. Subjects then completed a face-matching task while undergoing a functional magnetic resonance imaging scan.
Data analyses revealed that, compared with placebo, testosterone increased reactivity of the amygdala, hypothalamus and periaqueductal grey when viewing angry facial expressions.
"We were able to show for the first time that increasing levels of testosterone within the normal physiological range can have a profound effect on brain circuits that are involved in threat-processing and human aggression," said Carré, Assistant Professor at Nipissing University.
"Understanding testosterone effects on the brain activity patterns associated with threat and aggression may help us to better understand the ‘fight or flight’ response in males that may be relevant to aggression and anxiety," commented Dr. John Krystal, Editor of Biological Psychiatry.
Expanding our knowledge of exactly how testosterone affects the male brain is particularly important, as testosterone augmentation has become increasingly promoted and aggressively marketed as a solution to reduced virility in aging men. Further work is indeed continuing, Carré said. “Our current work is examining the extent to which a single administration of testosterone influences aggressive and competitive behavior in men.”
(Source: elsevier.com)
Study captures brain activity in children suffering emergence delirium
In a world-first, a newly published study has captured in detail the brain electrical activity in children as they emerge from anaesthesia, shedding light on why some are distressed and agitated when they wake up.
Researchers from Swinburne University of Technology together with colleagues from the Murdoch Childrens Research Institute (MCRI) were able to collect electroencephalography (EEG) data on children who exhibited emergence delirium.
Emergence delirium is a major risk associated with anaesthesia in children and occurs when patients wake up from anaesthesia in a delirious and disassociated state.
Swinburne Professor David Liley said PhD student Jessica Martin and staff at MCRI were able to record, with unprecedented fidelity, brain electrical activity from 60 children aged 5-15 years who emerged from anaesthesia some of whom went on to exhibit emergence delirium.
“This clinical phenomenon is prevalent in children aged six and under, with an estimated 10-30% exhibiting emergence delirium,” said Professor Liley.
Researchers found that the brain activity recorded just after stopping sevoflurane (a form of gas anaesthesia) in children exhibiting emergence delirium was substantially different to those children who woke up peacefully.
Associate Professor Andrew Davidson from MCRI said they discovered that children who wake up suddenly from a deeper plane of anaesthetic are more likely to develop the delirium.
“In contrast, the children who develop sleep like patterns on their EEG before they wake up are more likely to wake up peacefully.”
“Intriguingly, emergence delirium looks very much like the more severe form of night terror, which occurs when some pre-school children are disturbed during deep sleep.
“Our study suggests the EEG signatures and the mechanisms may indeed be similar between night terror and emergence delirium.
“Allowing children to wake up in a quiet and undisturbed environment should increase the likelihood that they go into a light sleep-like state after the anaesthetic and then wake up peacefully,” said Associate Professor Davidson.
The findings will have significant implications in both predicting those children who will go on to develop emergence delirium, as well as helping medical professionals better understand its causes in both children and adults.
The study, Alterations in the Functional Connectivity of Frontal Lobe Networks Preceding Emergence Delirium in Children, will appear in the October issue of the high profile clinical journal, Anesthesiology and is electronically available ahead of print.
(Source: swinburne.edu.au)
Medicinal oil reduces debilitating epileptic seizures associated with Glut 1 deficiency, trial shows
Two years ago, the parents of Chloe Olivarez watched painfully as their daughter experienced epileptic seizures hundreds of times a day. The seizures, caused by a rare metabolic disease that depleted her brain of needed glucose, left Chloe nearly unresponsive, and slow to develop.
Within hours, treatment with an edible oil dramatically reduced the number of seizures for then-4-year-old Chloe, one of 14 participants in a small UT Southwestern Medical Center clinical trial.
“Immediately we noticed fewer seizures. From the Chloe we knew two years ago to today, this is a completely different child. She has done amazingly well,” said Brandi Olivarez, Chloe’s mother.
For Chloe and the other trial participants who suffer from the disease called Glut1 deficiency (G1D), seizure frequency declined significantly. Most showed a rapid increase in brain metabolism and improved neuropsychological performance, findings that suggested the oil derived from castor beans called triheptanoin, ameliorated the brain glucose-depletion associated with this genetic disorder, which is often undiagnosed.
“This study paves the way for a medical food designation for triheptanoin, thus significantly expanding therapeutic options for many patients,” said Dr. Juan Pascual, Associate Professor of Neurology and Neurotherapeutics, Physiology, and Pediatrics at UT Southwestern and lead author of a study on the findings, published in JAMA Neurology.
For the estimated 38,000 Americans suffering from this disease, the only proven treatment has been a high-fat ketogenic diet, which only works for about two-thirds of patients. In addition, this diet carries long-term risks, such as development of kidney stones and metabolic abnormalities.
Based on the results of this trial, triheptanoin appears to work as efficiently as the ketogenic diet; however, more research needs to be done before the oil is made available as a medical food therapy, researchers said.
“Triheptanoin byproducts produced in the liver and also in the brain refill brain chemicals that we found are preferentially diminished in the disorder, and this effect is precisely what defines a medical food rather than a drug,” said Dr. Pascual, who heads UT Southwestern’s Rare Brain Disorders Program, maintains an appointment in the Eugene McDermott Center for Human Growth and Development, and holds The Once Upon a Time Foundation Professorship in Pediatric Neurologic Diseases.
The oil, approved for use in research only, is an ingredient in some cosmetic products and is added to butter in some European countries. It is not commercially available in the U.S. for clinical use.
Triheptanoin’s success as an experimental treatment for other metabolic diseases, along with preclinical success in G1D mice, led Dr. Pascual and his trial collaborator, Dr. Charles Roe, Clinical Professor of Neurology and Neurotherapeutics, to first conceive the idea and then launch this trial for G1D patients. The 14 pediatric and adult patients in the study consumed varying amounts of the oil, based on their body weight, four times a day. Given the trial’s success, Dr. Pascual plans further research to refine the optimal dosage toward the goal of facilitating medical food designation of triheptanoin as a new G1D treatment.
While some trial participants reported mild stomach upset as a side effect, for Chloe the oil has been a miracle medicine without negative effects. Her parents, Brandi and Josh Olivarez of Waco, Texas, continue to be amazed by her progress.
“Before, she was having so many seizures a day that she couldn’t even talk. Now she sings all the time, she can eat whatever she wants, and her speech is greatly improved. She still has some learning delays, but has come a long way,” said Mrs. Olivarez.
Many Glut1 patients suffer from movement disorders that limit their physical capabilities, but that does not appear to be the case with Chloe. As for the seizures, she still has minor ones occasionally, but they are not debilitating.
“She is now able to run a solid mile without stopping. This would not have been possible without the oil,” Mrs. Olivarez said. “Before, she had almost no muscle tone, was lethargic and had a very wide gait due to trying to balance herself while walking, which was very tiring for her.”
To better understand this disease, UT Southwestern established a patient-completed registry to track G1D incidence and what treatments work or do not work for those registered.
Important advance in brain mapping and memory
“When a tiger starts to move towards you, you need to know whether it is something you are actually seeing or whether it’s just something that you remember or have imagined,” says Prof. Julio Martinez-Trujillo of McGill’s Department of Physiology. The researcher and his team have discovered that there is a clear frontier in the brain between the area that encodes information about what is immediately before the eyes and the area that encodes the abstract representations that are the product of our short-term memory or imagination. It is an important advance in brain mapping and opens the doors to further research in the area of short-term memory.
These finding, which are described in an article just published in Nature Neuroscience, resolve a question that has occupied neuroscientists for years. Namely that of how and where exactly in the brain the visual information coming from our eyes is first transformed into short-term memories. “We found that while one area in the brain processes information about what we are currently seeing, an area right beside it stores the information in short-term memory,” says McGill PhD student Diego Mendoza-Halliday, first author of the article. “What is so exciting about this finding is that until now, no one knew the place where visual information first gets transformed into short-term memory.”
The researchers arrived at this conclusion by measuring the neuronal activity in these two areas in the brains of macaques as they first looked at, and then after a short time (1.2 - 2 seconds) remembered, a random sequence of dots moving across a computer screen like rainfall. What surprised Martinez-Trujillo and his team was how clearly demarcated the divide was between the activities and functions of the two brain areas, and this despite the fact that they lie side-by-side.
“It is rare to find this kind of sharp boundary in biological systems of any kind,” says Martinez-Trujillo. “Most of the time, when you look at the function of different brain areas, there is more of a transitional zone, more grey and not such a clear border between black and white. I think the evolutionary reason for this clear frontier is that it helped us to survive in dangerous situations.”
The discovery comes after five years spent by Martinez-Trujillo and his team doing research in the area. Despite this fact, he acknowledges that there was a certain amount of serendipity, and a lot of technological help involved in being able to capture a signal that travels for 3 milliseconds and fires synapses in neurons that lie right beside one another.
Martinez-Trujillo and his team continue to work on mapping the receptors and connectivity between these two areas of the brain. But what is most important for him is to try and relate this discovery to schizophrenia and other diseases that involve hallucinations, and in order to do so he is working with a psychiatrist at Montreal’s Douglas Hospital.
(Image: Bigstock)
Levels of vitamin D in newborn babies and multiple sclerosis show no connection
There was no association between levels of vitamin D in newborn babies and the risk of developing multiple sclerosis in adulthood. This is the observation made by researchers at Karolinska Institutet in a newly published study. The hypothesis could be tested with the help of the unique biobanks available in Sweden and at KI.
Multiple sclerosis (MS) is a chronic disease that affects the central nervous system, i.e., the brain and the spinal cord. Approximately 17,000 people in Sweden suffer from MS with the disease causing inflammations and lesions on the nerve fibres, preventing impulses from being received as they should be.
One hypothesis that has been widely discussed in recent years is on the link between low vitamin D levels in newborn babies and the risk of developing MS in adulthood. This hypothesis is based, amongst other things, on studies that have shown that those born in the spring have an increased risk of suffering from the disease when compared to those born in the autumn. The theory is that low vitamin D levels resulting from limited sun exposure during pregnancy increase the risk of MS in children born after the winter.
For the first time, researchers at Karolinska Institutet have been able to test this hypothesis which until now has only been assessed by indirect observations. Vitamin D levels at the birth of MS sufferers were measured and compared with those of control persons. The results have been published in the journal Annals of Neurology.
“We could not see any association between levels of vitamin D at birth and risk of MS in adulthood,” says Peter Ueda, researcher at the Department of Clinical Neuroscience and one of the researchers behind the study led by Tomas Olsson, Professor of Neurology at the same department and Lars Alfredsson, Professor at the Institute of Environmental Medicine.
“However a weaker link cannot be ruled out, nor can the link be ruled out for people with certain genes.”
“There are several reasons why the link between vitamin D at birth and later risk of MS has not been directly assessed previously,” explains Peter Ueda. As MS is a relatively uncommon disease, access to an entire population’s worth of blood samples that have been stored since birth would be required in order to provide reliable results. It must also be possible to trace the blood samples, preferably more than 30 years back in time– as this is the age around which the disease develop.
“Such biobanks are uncommon, however one can be found in Sweden. This study could be conducted due to the unique possibilities for monitoring and follow-up of patients in Sweden,” he says.
The study included 459 participants with MS and 663 healthy control participants. The participants were gathered from the EIMS project led by the Institute of Environmental Medicine at Karolinska Institutet in collaboration with neurology departments at hospitals in all Swedish counties. Each patient diagnosed with MS – in addition to control persons matched based on sex, age and place of residence – was asked to provide a blood sample and answer a questionnaire. The information is then saved and used for studies on the factors that cause MS.
Vitamin D levels from the time of birth of MS patients and their respective controls were determined with the help of the PKU register which contains blood samples from newborn Swedish people from 1975 onwards. For measuring vitamin D levels (25-hydroxy vitamin D) in dried blood samples, a a method developed by researchers at the University of Queensland, Australia was used.
Peter Ueda explains how results from the previously mentioned month of birth studies, that identified how those born in the spring had an increased risk of MS, had hinted of a potential opportunity to prevent a significant number of MS cases by ensuring that vitamin D levels in pregnant women are not too low.
“However, our results do not support the hypothesis of such a possibility for reducing MS risk,” he explains.
The lack of a link between vitamin D levels in newborns and the risk for MS remained, even when the researchers took into account certain factors that could affect the results – for example, month of birth, and the geographical latitude of birth, in as well as sun exposure and intake of vitamin D in adult age.
(Image: Helen Traherne)
People understand hyperbole through intent of communication
People tend to understand nonliteral language – metaphor, hyperbole and exaggerated statements – when they realize the purpose of the communication, according to new Stanford research.
Noah Goodman, an assistant professor of psychology at Stanford, believes that figurative language – the nuanced ways that people use language to communicate meanings different than the literal meaning of their words – is one of the deepest mysteries of human communication.
"Human communication," he said, "is rife with nonliteral language that includes metaphor, irony and hyperbole. When we say ‘Juliet is the sun’ or ‘That watch cost a million dollars,’ listeners read through the direct meanings – which are often false if taken literally – to understand subtle connotations."
'Sharp' vs. 'round' numbers
To understand this communication dynamic, Goodman, director of the Computation and Cognition Lab at Stanford, and his colleagues used computational modeling. Stanford graduate student Justine Kao was the first author on the paper, which included co-authors Jean Wu, a former graduate student at Stanford, and Leon Bergen of the Massachusetts Institute of Technology.
In their lab, they develop computational models that use pragmatic reasoning to interpret metaphorical utterances. Their research for this particular project involved four online experiments with 340 subjects.
Participants in the experiments read different scenarios involving hyperbole. For example, a person bought a watch and was asked by a friend whether it was expensive. That person responded with different figures, ranging from low- to high-cost figures – such as $50, $51, $10,000 or $10,001. Given this, the participants rated the probability of the purchaser thinking it was an expensive watch or not.
People tended to interpret “sharp numbers” – such as a watch costing $51 – more precisely than “round numbers,” as in a watch costing $50.
The findings suggest that even creative and figurative language may follow predictable and rational principles.
Kao said, “This research advances our understanding of communication by providing evidence that reasoning about a speaker’s goals is critical for understanding nonliteral language. We were able to capture nuanced and nonliteral interpretations of number words using a computational model.”
Common ground
The research showed that if listeners are trying to understand the topic and goal of communication as well as the underlying subtext – that which is not expressed explicitly – they’re better able to truly understand the utterance. A sense of common knowledge about what is being described or expressed is also important. Speakers and listeners assume that individuals are rational agents who use common ground and reference points to best maximize information.
As Kao put it, “There is still a long way to go before computers can understand Shakespeare, but it is a start.”
Goodman offered this example: Imagine someone describing a new restaurant, and she says, “It took 30 minutes to get a table.” People are most likely to interpret this to mean she waited about 30 minutes. But if she says, “It took a million years to get a table,” people will probably interpret this to mean that the wait was shorter than a million years, but that the person thinks it was much too long.
"One of the most fascinating facts about communication is that people do not always mean what they say – a crucial part of the listener’s job is to understand an utterance even when its literal meaning is false," the researchers wrote.
Goodman said the computational model he and his colleagues use to understand nonliteral utterances integrates empirically measured background knowledge, communication principles and reasoning about communication goals.
What is next in line research-wise?
Goodman and the others said they believe that the same ideas and techniques can extend to metaphor, irony and many other uses of language. For example, they have a promising initial exploration of “is a” metaphors such as “your lawyer is a shark,” Goodman said.
"Beyond these cases of figurative speech, the overall mathematical framework is beginning to give a precise theory of natural language understanding that takes into account context, intention and many subtle shades of meaning," he said, adding, "There is a lot more work to do."
(Source: news.stanford.edu)
On the frontiers of cyborg science
No longer just fantastical fodder for sci-fi buffs, cyborg technology is bringing us tangible progress toward real-life electronic skin, prosthetics and ultraflexible circuits. Now taking this human-machine concept to an unprecedented level, pioneering scientists are working on the seamless marriage between electronics and brain signaling with the potential to transform our understanding of how the brain works — and how to treat its most devastating diseases.
Their presentation is taking place at the 248th National Meeting & Exposition of the American Chemical Society (ACS), the world’s largest scientific society. The meeting features nearly 12,000 presentations on a wide range of science topics and is being held here through Thursday.
“By focusing on the nanoelectronic connections between cells, we can do things no one has done before,” says Charles M. Lieber, Ph.D. “We’re really going into a new size regime for not only the device that records or stimulates cellular activity, but also for the whole circuit. We can make it really look and behave like smart, soft biological material, and integrate it with cells and cellular networks at the whole-tissue level. This could get around a lot of serious health problems in neurodegenerative diseases in the future.”
These disorders, such as Parkinson’s, that involve malfunctioning nerve cells can lead to difficulty with the most mundane and essential movements that most of us take for granted: walking, talking, eating and swallowing.
Scientists are working furiously to get to the bottom of neurological disorders. But they involve the body’s most complex organ — the brain — which is largely inaccessible to detailed, real-time scrutiny. This inability to see what’s happening in the body’s command center hinders the development of effective treatments for diseases that stem from it.
By using nanoelectronics, it could become possible for scientists to peer for the first time inside cells, see what’s going wrong in real time and ideally set them on a functional path again.
For the past several years, Lieber has been working to dramatically shrink cyborg science to a level that’s thousands of times smaller and more flexible than other bioelectronic research efforts. His team has made ultrathin nanowires that can monitor and influence what goes on inside cells. Using these wires, they have built ultraflexible, 3-D mesh scaffolding with hundreds of addressable electronic units, and they have grown living tissue on it. They have also developed the tiniest electronic probe ever that can record even the fastest signaling between cells.
Rapid-fire cell signaling controls all of the body’s movements, including breathing and swallowing, which are affected in some neurodegenerative diseases. And it’s at this level where the promise of Lieber’s most recent work enters the picture.
In one of the lab’s latest directions, Lieber’s team is figuring out how to inject their tiny, ultraflexible electronics into the brain and allow them to become fully integrated with the existing biological web of neurons. They’re currently in the early stages of the project and are working with rat models.
“It’s hard to say where this work will take us,” he says. “But in the end, I believe our unique approach will take us on a path to do something really revolutionary.”
'Seeing' through Virtual Touch Is Believing
A University of Cincinnati experiment aimed at this diverse and growing population could spark development of advanced tools to help all the aging baby boomers, injured veterans, diabetics and white-cane-wielding pedestrians navigate the blurred edges of everyday life.
These tools could be based on a device called the Enactive Torch, which looks like a combination between a TV remote and Captain Kirk’s weapon of choice. But it can do much greater things than change channels or stun aliens.
Luis Favela, a graduate student in philosophy and psychology, has found the torch enables the visually impaired to judge their ability to comfortably pass through narrow passages, like an open door or busy sidewalk, as good as if they were actually seeing such pathways themselves.
The handheld torch uses infra-red sensors to “see” objects in front of it. When the torch detects an object, it emits a vibration – similar to a cellphone alert – through an attached wristband. The gentle buzz increases in intensity as the torch nears the object, letting the user make judgments about where to move based on a virtual touch.
"Results of this experiment point in the direction of different kinds of tools or sensory augmentation devices that could help people who have visual impairment or other sorts of perceptual deficiencies. This could start a research program that could help people like that," Favela says.
Favela presented his research “Augmenting the Sensory Judgment Abilities of the Visually Impaired” at the American Psychological Association’s (APA) annual convention, held Aug. 7-10 in Washington, D.C. More than 11,000 psychology professionals, scholars and students from around the world annually attend APA’s convention.
A Growing Population in Need
Favela studies how people perceive their environment and how those perceptions inform their judgments. For this experiment, he was inspired by what he knew about the surging population of visually impaired Americans.
The Centers for Disease Control and Prevention (CDC) predicts that more than 6 million Americans age 40 and older will be affected by blindness or low vision by 2030 – double the number from 2004 – due to diabetes or other chronic diseases and the rapidly aging population. The CDC also notes that vision loss is among the top 10 causes of disability in the U.S., and vision impairment is one of the most prevalent disabilities in children.
"In my research I’ve found that there’s an emotional stigma that people who are visually impaired experience, particularly children," Favela says. "When you’re a kid in elementary school, you want to blend in and be part of the group. It’s hard to do that when you’re carrying this big, white cane."
Substituting Sight with Touch
In Favela’s experiment, 27 undergraduate students with normal or corrected-to-normal vision and no prior experience with mobility assistance devices were asked to make perceptual judgments about their ability to pass through an opening a few feet in front of them without needing to shift their normal posture. Favela tested participants’ judgments in three ways: using only their vision, using a cane while blindfolded and using the Enactive Torch while blindfolded. The idea was to compare judgments made with vision against those made by touch.
The results of the experiment were surprising. Favela figured vision-based judgments would be the most accurate because vision tends to be most people’s dominant perceptual modality. However, he found the three types of judgments were equally accurate.
"When you compare the participants’ judgments with vision, cane and Enactive Torch, there was not a significant difference, meaning that they made the same judgments," Favela says. "The three modalities are functionally equivalent. People can carry out actions just about to the same degree whether they’re using their vision or their sense of touch. I was really surprised."
Favela plans additional experiments requiring more complicated judgments, such as the ability to step over an obstacle or to climb stairs. With further study and improvements to the Enactive Torch, Favela says similar tools that augment touch-based perception could have a significant impact on the lives of the visually impaired.
"If the future version of the Enactive Torch is smaller and more compact, kids who use it wouldn’t stand out from the crowd, they might feel like they blend in more," he says, noting people can quickly adapt to using the torch. "That bodes well, say, for someone in the Marines who was injured by a roadside bomb. They could be devastated. But hope’s not lost. They will learn how to navigate the world pretty quickly."
(Source: uc.edu)